Electrical conductor



June 1935- D R. G. PALMER 2,004,901

ELECTRICAL CONDUCTOR Filed Dec. 18, 1925 E. 1 TE. E TE- 5 Tsfi T315 1 NVEN TOR.

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Patented June 11, 1935 UNITED STATES PATENT OFFICE- ELECTRICAL CONDUCTORDwight R. G. Palmer, South Orange, N. 1., as-

signor to General Cable Corporation, New York, N. Y., a corporation ofNew Jersey- Application December 18, 1925, Serial No. 76,182

7 Claims. (Cl. 173-267) My invention relates broadly to electricalconconductors housed within a flexible metallic ductors and moreparticularly to a construction armor. In two conductor cable one wireconof electrical conductor particularly adapted for veys the current tothe service outlet while the use in the wiring of buildings andresidences for other wire is grounded or in neutral and provides powerand lighting current supply to outlets the return channel. Bothconductors are gener- 5 throughout the building. ally rubber insulatedand are mechanically pro- One of the objects of my invention is toprotected by the use of cotton braids or with other vide an electricalassembly which may be maninsulating or metallic protection. I provide anufact-ured more inexpensively than assemblies insulated metallicconductor and an uninsulated heretofore employed for performing the sameconductor of non-corrosive metal which extends 10 service, where lessmaterial is required in the parallel to, adjacent to, or is spiralledaround manufacture of the assembly and smaller overthe insulatedconductor forming a member adall size of the assembly is secured thanhas hereiacent to the insulated condu t r 0r conductors tofore beenpossible in wiring constructed for. and the inner walls of the metallicarmor or 5 a similar purpose. sheathing. By virtue of the relativelysmall nother Object of my invention is to provide diameter of theuninsulated conductor the outer a conductor in which a housingsheath isarmetallic armor or sheathing is substantially ranged to enclose aninsulated and uninsulated smaller in diameter than the diameter ofarmored electrical conductor where the uninsulated eleca le heretoforerequired in this w A u 90 trical conductor lies adjacent the interiorwalls Stantlal saving in the material in the manufacof the sheath, theinsulated conductor being for ture' of the assembly is thereforeObtainedthe purpose of carrying current while the unin- Referring to thedrawing in more detail, refersulated conductor serves for the groundedside ence character I designates a metallic cond tor; of the circuit,that is the neutral conductor, and 2 an insulat n v in 3 a raid o raidsth r 95 for polarity identification. over impregnated or finished with amoisture re- By reason of the construction of the conducpellent. Aflexible metallic armor 4 encases the tor which I provide, Iam enabledto save concovered conductor I and interposed between the siderablematerial in its manufacture and yet outer covering 3 and the inner wallof the sheathprovide a safe electrical conductor for performing Iprovide an auxiliary conductor 5 of noning all of the functions of moreexpensive conc os ve m ta-L AS represented in F g. 1, the 3 ductorsheretofore available in the art. auxiliary conductor 5 extends parallelto the in- My invention will be more fully understood sulated conductorI, while in Fig. 2 the conductor from the following specification byreference to 5 is twisted around the insulated conductor and theaccompanying drawing, wherein: utilizes the armor as a joint ground. InFig. 3 5 Figure 1 is side elevation of an armored cable I have shown thecovered conductor l encased in partially broken away to illustrate theprinciple a sheath 6 of fibrous material with the auxiliary of myinvention; Fig. 2 is a modified view oi an conductor 5 extendingparallel to the covered conarmored cable in which the neutral conductorductor I and immediately beneath the sheath 8. serves both as amechanical spacing member for In 4 a C du o C stru d in co dance theinsulated conductor and as the grounding with the conductor of Fig. 3has been illustrated, 40 side of a circuit; Figs. 3 and 4 showapplications but the auxiliary conductor 5 is spiralled beneath of myinvention to electrical conductors prothe fibrous protector 6. videdwith insulated sheaths under which the In Fig. 5 I have shown theconductor of my polarity identification conductor is arranged; Fig.invention housed within a stiff metallic conduit 1 5 is a fragmentaryview of the conductor of my with the auxiliary conductor 5 immediatelyad- 45 invention housed within a metallic or other conjacent the outersurface of the covering 3 in a duit; Figs. 6, 7, 8, 9 and 10 arecross-sectional position to establish electrical connection with viewstaken on lines 66, 88, 9-9 and the interior walls of the conduit 1.Illl1l of Figs. 1, 2, 3, 4 and 5, respectively; Fig. In Flg. 11 I haveshown by reference character 11 shows the comparative saving in materialin 8 the usual armored cable conductor in which 50 the assembly of myinvention over the assembly twin conductors 9, each separately insulatedare heretofore available in the art. encased, the conduit having adiameter rep- In the standard wiring of buildings or resiresented at A.In my construction the diameter dences it is customary to employflexible arm- B of the flexible conduit is substantially smaller oredcable constituted by two or more insulated than the correspondingdiameter A. This con- 55 struction brings about a saving in the cost ofmanufacture of the cable, the assembly cost, and reduces the expense inmaterial cost by saving the expense of insulation of neutral conductor 5and reducing the necessary diameter of the flexible conduit 4.

I have found that electrical conductors manuiactured in accordance withmy invention, de-

' scribed herein, is practical in manufacture and and a pair of flexiblemetallic members helically woundaround said insulating covering, one ofsaid pair of flexible members having a substantially circularcross-section and serving as a bare neutral conductor, and the other ofsaid pair of flexible members being in the form of a band wound inoverlapping and interlocking relation over said aforementioned flexiblemember of said pair for providing a flexible casing around Saidinsulated member and the other helically wound member. c

2. An electrical cable comprising a flexible conductor, an insulatingcovering for said conduc tor, and a pair of flexible metallic membershelically spirally wound around said insulating covering and having awinding pitch differing one from the other, one of said helical membersbeing wrapped about said insulating covering and serving as a bareneutral conductor and the other of said helical members beingconstituted by a helically wound interlocking member in electrical andmechanical contact with said aforementioned helical member for encasingsaid insulating covering.

3. An electrical cable of the class described comprising, incombination, an insulated live wire conductor, a flexible, helical,metal armor closely surroundingthe insulated lives-wire conductor, and abare neutral or return conductor adapted to be connected with thegrounded side of the line, said bare neutral conductor being disposedhelically between the armor and the insulated conductor and inelectrical contact with the former.

4. An electrical cable of the class described comprising, in combinationan insulated live-wire conductor, a flexible, helical, metal armorclosely surrounding the insulated live-wire conductor, and a bareneutral or return conductor adapted to be connected with the groundedside of the line, said bare neutral conductor disposed helically betweenthe armor and the insulated conductor and in electrical contact with theformer, the helix 0f the bare neutral conductor being of longerconvolutions than the helix of the armor, the cable thus constitutedbeing small, equally flexible in all directions and of substantiallyuniform over-all dimensions.

5. An electrical cable of'the class described, comprising, incombination, an insulated livewire conductor, a flexible, helical, metalarmor closely surrounding the insulated live-wire conductor, and a bareneutral or return conductor disposed helically between the armor and theinsulated conductor and in electrical contact with the armor, said bareneutral conductor being arranged in much longer convolutions than thearmor and being of small dimension radially of the cable; i

6. An electric cable comprising, in combina tion, an insulated live-wireconductor, this wire with its insulation being circular incross-section, a bare neutral orreturn wire disposed helically in longconvolutions about the insulated conductor, said bare conductor having arelatively small dimension radially of the conductor, anda flexible,helical, metal armor applied in shorter convolutions about bothconductors, the whole being a small uniformly flexible cable ofsubstantially uniform over-all dimensions, suitable for housewiring.

'7. An electrical cable comprising, in combination, a flexibleconductor, an "insulating covering for said conductor, a bare neutralconductor adapted to beconnected with the'grounded side of acircuitwound helically around the insulated conductor, and a flexible,helically wound metallic armor of shorter lay than the bare neutralconductor surrounding the insulated and bare neutral conductors, thebare neutral con- DWIGHT G. PALMER.

